The present invention concerns control apparatus particularly but not exclusively useful for a short take-off and vertical landing (STOVL) aircraft having one or more engine(s), usually gas turbine jet engine(s) and vectorable or swivellable nozzle(s) pivotable between a substantially horizontal position for wing-borne flight and a substantially vertical position for jet-borne flight, e.g. vertical take-off, hovering and vertical landing.
Control apparatus for aircraft usually includes a control lever forming part of a thrust demand unit or throttle box by means of which a pilot or an auto-pilot mechanism may control the forward/idle/reverse thrust operation of aircraft.
The invention is concerned with control levers of the type which are responsive, without movement, to progressive force application by the operator. The control levers may then be force throttles. The term "force throttle" means an engine control device including a throttle lever which is not mechanically linked to the associated apparatus, i.e. engine fuel control system, but is linked by a system of force sensors, sensing the attempted movement of the lever by the operator, and electrical, optical or other non-mechanical signal transmission lines to suitable transducers and actuators for mechanically operating the engine fuel control system. Such mechanical counterparts, and typically the lever may be small enough to be operated single-handedly by the pilot using only his thumb and forefinger to apply demand pressure.
In EP-A-0,326,439 the priority application of which forms the basis of U.S. Pat. No. 4,982,918, I have described and claimed a force throttle responsive to forces exerted thereon by an operator, a handle pivoted on the lever of the force throttle for rotation about an axis transverse to a direction of application of said forces, and means for rotating said handle to predetermined angular positions dependent on said forces and each indicative of a separate one of a plurality of thrust demands required of an associated gas turbine engine to which in use said force throttle is to be connected.
The force-throttle described in EP-A-326,439 is well able to control thrust, but is limited to that function and separate control apparatus is required for other control purposes. In particularly, for a STOVL aircraft the pilot would require a separate control member (lever) for controlling the orientation of vectorable nozzle means.
However, this is a disadvantage for modern aircraft where the aim must be not to overload the operator. This is particularly important in a military aircraft application where ever increasing demands are made of pilots of modern fighter aircraft. In addition to flying the aircraft the pilot is often required to manage complex weapons, electronic counter-measures, electronic surveillance, electronic navigation, computer and communications systems. Moreover, the control member should take up the minimum amount of available space.